From Password Recovery Procedure for the Cisco 2600 and 2800 Series Routers.

  1. Connect Console Cable
  2. Start minicom
  3. Configure Serial Communication Settings for minicom
  4. Reset Cisco Password

Connect Console Cable

  1. Connect the serial cable to the PC and to the device's Console port

Start minicom

  1. Start minicom from a terminal window
      minicom
      

Configure Serial Communication Settings for minicom

  1. Set the proper serial terminal settings (9600 bps, 8N1)
    1. First, you need to get to the point of configuring minicom:
      • Press Ctrl-A
      • Press Z
    2. Now configure the terminal settings:
      • Press P for comm Parameters
      • Press C for 9600 baud
      • Verify that the line near the top reads 9600 8N1
      • Press Enter key to accept and exit configuration

Reset Cisco Password

After making sure you have done all of the above steps:

  1. Power off the device, and keep it off until later.

    Password reset works when the device is powering up, but we have to do something special before powering on.

  2. In minicom, get to the configuration window:
  3. Power on the device, and nearly immediately (within a minute) press F in the minicom configuration to send break to the device.
  4. You should see the following:
    Readonly ROMMON initialized                                               
    rommon 1 >
      
  5. Set up to boot from flash (enter the following command):
      confreg 0x2142
      
  6. Reboot from flash, ignoring the saved configuration:
      reset
      
  7. When presented with setup questions, enter Ctrl-C to bypass them all. You should then see:
    Press RETURN to get started!   
      

    Press the Enter key, and you should eventually see:

      Router>
      
  8. Get into privileged mode:
      enable
      

    You should then see:

      Router#
      
  9. Copy the startup configuration to the running configuration:
      copy start run
      

    If it prompts you for running-config, press Enter to accept.

  10. Look at the running configuration:
      show run
      
  11. Configure the terminal:
      config t
      
  12. Set the password to cisco:
      enable secret cisco
      
  13. End the configuration of the terminal:
      end
      

    Messages may appear unsolicited after that; press Enter to see the prompt again.

  14. Look at your interfaces -- you want them to be down (next step):
      show ip interf brief
      
  15. Bring up all interfaces -- use no shutdown on all interfaces.

    For example, if only FastEthernet0/0 is showing down:

      config t
      interface FastEthernet0/0
      no shutdown
      end
      
  16. Set up the configuration register.
      config t
      config-register 0x2102
      
  17. Leave configuration mode:
      end
      
  18. Commit the changes by copying the running configuration to the startup configuration:
      copy run start
      
  19. Restart the device:
      reload